黄芪多糖对放射性肠炎大鼠肠黏膜损伤的修复作用研究

Study on the Repairing Effect of Astragalus Polysaccharide on Intestinal Mucosal Injury in Rats with Radiation Enteritis

【目的】探讨黄芪多糖对放射性肠炎大鼠肠黏膜损伤的修复作用及机制。【方法】取48只SD大鼠采用高能X射线全腹照射建立放射性肠炎模型,造模成功后随机分为模型组(12只)、黄芪多糖组(12只)、复合物C组(12只)、黄芪多糖+复合物C组(12只),另取12只大鼠置于相似环境但不给予照射作为正常组。黄芪多糖组给予400 mg/kg黄芪多糖灌胃,复合物C组给予2 mL复合物C 10μmol/L灌胃,黄芪多糖+复合物C组给予400 mg/kg黄芪多糖、2 mL复合物C 10μmol/L灌胃,正常组、模型组实验期间灌胃等体积无菌生理盐水,每日1次,连续7 d。观察大鼠一般情况并进行疾病活动指数(DAI)评分;荧光素示踪法检测大鼠小肠黏膜通透性;酶联免疫吸附分析(ELISA)检测大鼠小肠黏膜组织白细胞介素1β(IL-1β)、肿瘤坏死因子α(TNF-α)水平;苏木素-伊红(HE)染色法和透射电镜观察大鼠小肠黏膜组织病理学和绒毛超微结构变化;蛋白免疫印迹(Western Blot)法检测小肠黏膜组织腺苷酸活化蛋白激酶(AMPK)通路相关蛋白表达水平。【结果】与模型组比较,黄芪多糖组DAI、血浆硫氰酸荧光素标记的葡聚糖4(FD4)含量、小肠黏膜组织IL-1β和TNF-α水平、磷酸化哺乳动物雷帕霉素靶蛋白(p-mTOR)相对表达量降低,p-AMPK蛋白相对表达量升高(P<0.05),肠黏膜损伤程度减轻;与模型组比较,复合物C组DAI、血浆FD4含量、小肠黏膜组织IL-1β和TNF-α水平、p-mTOR相对表达量升高,p-AMPK蛋白相对表达量降低(P<0.05),肠黏膜损伤程度加重。与黄芪多糖组比较,复合物C组、黄芪多糖+复合物C组DAI、血浆FD4含量、小肠黏膜组织IL-1β和TNF-α水平、p-mTOR相对表达量升高,p-AMPK蛋白相对表达量降低(P<0.05),肠黏膜损伤程度加重。与复合物C组比较,黄芪多糖+复合物C组DAI、血浆FD4含量、小肠黏膜组织IL-1β和TNF-α水平、p-mTOR相对表达量降低,p-AMPK蛋白相对表达量升高(P<0.05),肠黏膜损伤程度减轻。【结论】黄芪多糖可以修复放射性肠炎大鼠肠黏膜损伤,其作用机制可能与激活AMPK通路有关。

Objective To explore the repairing effect and mechanism of astragalus polysaccharide(APS)on intestinal mucosal injury in rats with radiation enteritis(RE).Methods Forty-eight SD rats were irradiated with high energy X-rays to establish a rat model of RE.After successful modeling,the rats were randomly divided into the model group(12 rats),the APS group(12 rats),the complex C group(12 rats),the APS+complex C group(12 rats),and another 12 rats were placed in similar environment without irradiation as normal group.The APS group was given 400 mg/kg APS intragastric administration,complex C group was given 2 mL complex C 10μmol/L intragastric administration,APS+complex C group was given 400 mg/kg APS,2 mL complex C 10μmol/L intragastric administration.Normal group and model group were given equal volume of sterile normal saline intragastric administration.All the treatments placed once a day for consecutive 7 days.The general condition of rats was observed and disease activity index(DAI)score was performed.The permeability of small intestinal mucosa was detected by fluorescein tracer.The levels of interleukin 1β(IL-1β)and tumor necrosis factorα(TNF-α)in intestinal mucosal tissues were detected by enzyme-linked immunosorbent assay(ELISA).The histological changes of small intestinal mucosa and ultrastructure of villi were observed by hematoxylin-eosin(HE)staining and transmission electron microscopy.Western Blot method was used to detect the expression levels of adenosineactivated protein kinase(AMPK)pathway-related proteins in intestinal mucosal tissues.Results Compared with the model group,the DAI,plasma fluorescein thiocyanate labeling dextran 4(FD4)content,intestinal mucosal IL-1βand TNF-αlevels,relative protien expression level of phosphorylated mammalian target of rapamycin(pmTOR)were decreased,and the relative protein expression level of p-AMPK in APS group was alleviated(P<0.05),and the degree of intestinal mucosal injury was reduced;compared with the model group,the DAI,plasma FD4 content,small intestinal mucosal tissue IL-1βand TNF-αlevels,relative protein expression level of p-mTOR were increased,the relative protein expression level of p-AMPK was decreased in the complex C group,and the degree of intestinal mucosal damage was increased.Compared with the APS group,the DAI,plasma FD4 content,small intestinal mucosal tissue IL-1βand TNF-αlevels,p-mTOR relative expression level were increased and p-AMPK relative protein expression was decreased in the complex C group and APS+complex C group(P<0.05),and the degree of intestinal mucosal injury was increased.Compared with complex C group,DAI,plasma FD4 level,IL-1βand TNF-αlevels in small intestinal mucosal tissue,relative expression level of p-mTOR were decreased,and relative expression level of p-AMPK was increased in APS+complex C group(P<0.05),and the degree of intestinal mucosal damage was reduced.Conclusion APS can repair intestinal mucosal damage in rats with RE,and its mechanism of action may be related to the activation of AMPK pathway.